Field of the Invention
The invention relates to a method for optimizing a magnetic resonance sequence of a magnetic resonance apparatus, a method for operating a magnetic resonance apparatus, a sequence optimizing device, a magnetic resonance apparatus and a non-transitory, computer-readable data storage medium encoded with programming instructions to implement such methods.
Description of the Prior Art
In a magnetic resonance apparatus, also known as a “magnetic resonance tomography system”, the body to be examined, particularly that of a patient, is typically exposed to a relatively strong magnetic field of, for example, 1.5 or 3 or 7 Tesla, with the use of a basic field magnet. In addition, gradient pulses are applied with the operation of a gradient coil unit. By the operation of a radio frequency antenna unit, using suitable antennas, radio frequency pulses, particularly excitation pulses, are transmitted, which cause nuclear spins of particular atoms, excited into resonance by these radio frequency pulses, to be tilted through a defined flip angle relative to the magnetic field lines of the basic magnetic field. During relaxation of the nuclear spin, radio frequency signals known as “magnetic resonance signals” are emitted and are received by suitable radio frequency antennas and then further processed. From the raw data thereby acquired, the desired image data can ultimately be reconstructed.
For a particular data acquisition, a particular magnetic resonance sequence, known as a pulse sequence composed of a sequence of radio frequency pulses, in particular excitation pulses and refocusing pulses, as well as gradient pulses to be transmitted suitably coordinated therewith on various gradient axes along different spatial directions, is to be transmitted. Temporally adapted thereto, readout windows are set which pre-determine the time frames within which the induced magnetic resonance signals are detected. Of decisive importance for the imaging is particularly the timing within the sequence, that is, at what temporal spacing which gradient pulses follow one another. A large number of the control parameters are typically defined in a “measuring protocol” which is created in advance and can be retrieved for a particular measurement, for example, from a memory store and, if necessary, can be modified by the user on site who can stipulate additional control parameters such as, for example, a particular slice increment of a batch of slices to be scanned, a slice thickness, etc. Then, based on all these control parameters, a magnetic resonance sequence is calculated.